| _version_ | 1867171583409258496 |
|---|---|
| author | Meissl, Sandra Behrmann, Jan-Hinrich Franke, C |
| author_facet | Meissl, Sandra Behrmann, Jan-Hinrich Franke, C |
| collection | Datos científicos de ciencias marinas y ambientales |
| contents | The continental slope of the northern Gulf of Mexico seaward of the Mississippi Delta is characterized by very rapid Quaternary sedimentation. Thick sequences of underconsolidated muds and mudstones are present, which are severely overpressured. In the Ursa Basin, Site U1322 of the Integrated Ocean Drilling Program (IODP) provided an excellent coring record of interleaved fine-grained turbidites and hemipelagic sediments, in part severely affected by submarine slumping and sliding after deposition. Cores were continuously sampled and analyzed for anisotropy of magnetic susceptibility (AMS), to elucidate the effects of different transport mechanisms and degree of settling and consolidation on magnetic fabric properties. Generally AMS ellipticity increases with depth irrespective of transport mode, due to loss of porosity. Samples from slumped mass transport deposits (MTD), however, have higher AMS if compared to immediately overlying nonslumped material. MTD samples dominantly show triaxial magnetic fabrics whereas those found in nonslumped sediments are much more oblate. Long axes of the fabric ellipsoid reflect the direction of eastward to southward suspension transport in samples not overprinted by sliding or slumping. Short ellipsoid axes in non-slumped material are vertical, and thus parallel to the axis of maximum uniaxial shortening. In the MTD samples, many short ellipsoid axes are inclined, reflecting an overprint of the uniaxial shortening by bedparallel shearing induced by the slumping. Shear and MTD transport direction deduced from the fabrics is top to- SE, downslope along the morphological axis of Ursa Basin. Generally we show that magnetic fabrics of muds and mudstones are sensitive recorders of sedimentary and tectonic processes, and can be used to reconstruct essential |
| format | Dataset Open Access |
| id | pangaea_https___doi_org_10_1594_PANGAEA_787621 |
| institution | PANGAEA |
| language | en |
| publishDate | 2011 |
| publisher | PANGAEA |
| record_format | pangaea |
| spellingShingle | (Table 1) Magnetic susceptibility from IODP Hole 308-U1322B Meissl, Sandra Behrmann, Jan-Hinrich Franke, C 308-U1322B; Anisotropy-magnetic susceptibility, factor F, foliation; Anisotropy-magnetic susceptibility, factor L, lineation; Anisotropy-magnetic susceptibility, factor P, anisotropy degree; Corrected; Declination of principle axis K1; Declination of principle axis K2; Declination of principle axis K3; DEPTH, sediment/rock; DRILL; Drilling/drill rig; DSDP/ODP/IODP sample designation; Exp308; Gulf of Mexico Hydrogeology; Inclination of principle axis K1; Inclination of principle axis K2; Inclination of principle axis K3; Integrated Ocean Drilling Program / International Ocean Discovery Program; IODP; Joides Resolution; Magnetic tool face angle; Principle axes K1 of normalized anisotropy tensor; Principle axes K2 of normalized anisotropy tensor; Principle axes K3 of normalized anisotropy tensor; Sample, optional label/labor no; Sample code/label; Shape of susceptibility; Susceptibility; Susceptibility unit Kappabridge KLY-2; Unit The continental slope of the northern Gulf of Mexico seaward of the Mississippi Delta is characterized by very rapid Quaternary sedimentation. Thick sequences of underconsolidated muds and mudstones are present, which are severely overpressured. In the Ursa Basin, Site U1322 of the Integrated Ocean Drilling Program (IODP) provided an excellent coring record of interleaved fine-grained turbidites and hemipelagic sediments, in part severely affected by submarine slumping and sliding after deposition. Cores were continuously sampled and analyzed for anisotropy of magnetic susceptibility (AMS), to elucidate the effects of different transport mechanisms and degree of settling and consolidation on magnetic fabric properties. Generally AMS ellipticity increases with depth irrespective of transport mode, due to loss of porosity. Samples from slumped mass transport deposits (MTD), however, have higher AMS if compared to immediately overlying nonslumped material. MTD samples dominantly show triaxial magnetic fabrics whereas those found in nonslumped sediments are much more oblate. Long axes of the fabric ellipsoid reflect the direction of eastward to southward suspension transport in samples not overprinted by sliding or slumping. Short ellipsoid axes in non-slumped material are vertical, and thus parallel to the axis of maximum uniaxial shortening. In the MTD samples, many short ellipsoid axes are inclined, reflecting an overprint of the uniaxial shortening by bedparallel shearing induced by the slumping. Shear and MTD transport direction deduced from the fabrics is top to- SE, downslope along the morphological axis of Ursa Basin. Generally we show that magnetic fabrics of muds and mudstones are sensitive recorders of sedimentary and tectonic processes, and can be used to reconstruct essential |
| title | (Table 1) Magnetic susceptibility from IODP Hole 308-U1322B |
| topic | 308-U1322B; Anisotropy-magnetic susceptibility, factor F, foliation; Anisotropy-magnetic susceptibility, factor L, lineation; Anisotropy-magnetic susceptibility, factor P, anisotropy degree; Corrected; Declination of principle axis K1; Declination of principle axis K2; Declination of principle axis K3; DEPTH, sediment/rock; DRILL; Drilling/drill rig; DSDP/ODP/IODP sample designation; Exp308; Gulf of Mexico Hydrogeology; Inclination of principle axis K1; Inclination of principle axis K2; Inclination of principle axis K3; Integrated Ocean Drilling Program / International Ocean Discovery Program; IODP; Joides Resolution; Magnetic tool face angle; Principle axes K1 of normalized anisotropy tensor; Principle axes K2 of normalized anisotropy tensor; Principle axes K3 of normalized anisotropy tensor; Sample, optional label/labor no; Sample code/label; Shape of susceptibility; Susceptibility; Susceptibility unit Kappabridge KLY-2; Unit |
| url | https://doi.org/10.1594/PANGAEA.787621 |